Television camera lens switching device



6, 1949. T, W CHEW TELEVISION CAMERA LENS swITcaINc- DEVICE Filed June 4, 1945 3 Sheets-Sheet l QN E vv.. QN ,NNN @w E E Thor/afan W Clica)- Sp., 6, 1949. T, w CHEW 2,481,082

TELEVISION CAMERA LENS SWITCHINGIDEVICE Filed June 4, 1945 3 Sheets-Sheet 2 Sept., 6, E949. T. W. CHEW TELEVISION CAMERA LENS swITcHING DEVICE 3 Sheets-Sheet 5 Filed June 4, 1945 Patentecl Sept. 6, 1949 UNITED STATES PATENT OFFICE TELEVISION CAMERA LENS SWITCHING DEVICE Thornton W. Chew,

Washington, D. C. Application June 4, 1945, Serial No.

4 Claims. (Cl. 95-44) of a plurality of lengths.

In the use of motion cameras it has heretofore t is accordingly one of the objects of the pres- I ent invention to provide a novel lens system for A further object resides in the provision of a novel lens system of the foregoing type which is so arranged as to avoid the necessity of shifting the lenses, the construction being such that throughout the several villustrating a television a relatively sunple angle lens;

Fig. 3 is a View position of the angle lens;

Fig. 4 is a diagrammatic view of still another similar to Fig. 2 but showing the parts when employing the Wide form of the invention wherein the mirrors are comprised of relatively movable sections;

Fig. 5 is a diagrammatic View of the mechanism of Fig. 4 but illustrating a dilierent type of actuating mechanism for the mirror sections;

which is employed in Figs.2 and 3.

Referring more particularly to Fig. 1, the present invention is illustrated therein as being associated with atelevision camera I0, having a casing l2 adapted to house a scanning tube I4, the latter bein usual photov.other ratios may .be used, depending upon novel construction including mirrors 2l) and 22, and a shutter 23, are adapted to selectively transmit light rays from an object 24 to the mosaic of tube I4.

In order to provide the abovenmentioned selective operation of the lenses I6 and I8, mirror 23 is fixedly.mountedwithin'fthe camera, in any suitablemanner, and isprovidedwith a reflecting surface on the side facing the lens I6. Mirror 22 on the other hand, is of a special type and is formed by a clear glass plate having a plurality of spaced-apart silvered islands thereon, the arrangement being such that the total areas of the silvered and clear glass -are substantially equal so that the mirror is capableof transmitting images with approximately the same efficiency as its capability of reflecting images. While the aforementioned ratios of reflecting and transmitting .areas will usually Ybe-:found to be the most desirable, .it will -be yunderstood `that vthe particulareffects to be obtained.

For the purpose vof Yselecting the llens to be used at the desiredmoment,-the shutter23, which may be shiftedup'ondownby any suitable actuating 'device 26 whichisspreferably remotely controlled, is provided V`with-a light intercepting portion 28 and a lighttransmitting POI-tion 30, these parts being rso dimensioned and positioned with respect to the lenses I6 and I8, that during movement of the shu ter, Fthe transmission of one lens image -will Vincrease atsubstantially the same rate transmission as the other lens image is decreased. Thus the arrangement secures a lap-dissolve .effect in shifting from one position to the other.

In operation and withv -the `,parts arranged in the position shown, the mirror 2-.2 will Ytransmit the @image Afrom -the wideangle lens I8 to ythe tube I4 through the -clearg-lass portion thereof, the image :from thenarrow Vangle'lens I6 being blocked by theshutter lportion 128. If itis now desired to utilizelthe lens 46, it-is onlynecessary to shift the shutter 23 downwardly whereupon `the transmission-ofthe'image1from-lens I6 `will increase-while thetransmission'of-the image from lens I8 will decrease at 4substantially Athe same rate until a point isi-reached when light 'transmission from lens L8 -is y.blocked vQby-the shutter portion 28. At such time, complete transmission of the image from lens I6 to -the tube I4 will be effected byfmeans .of mirror.2ILandthe reflecting portions of mirror 22. Thus the shift from one lens to another is acco plished in a simple and efficient manner -which requires only vthe movement of the shutter 23 which ymay be very 4light in Iweight and :fastin its action.

In the form of the invention illustrated in Figs. 2 and 3, the selection 'of thedesired lens is effected by vmechanically :changing Ythe `position .of one of' the mirrors of cthe optical-system. fMore particularly, special ymirror 22 of -Fig..l has been yreplaced by a mirror 32 of the usual type which is provided with a reflecting surface opposed `to ,the reflecting `surface-of the mirror 20. The mirror 32 'is moreoverzsutably'pivoted at 34 to a stationary part Vand is associated with va novel shutter and mirror shifting .mechanism -36 so that the images vfrom the lenses VI6 and I8 may be shifted as clearly'shown in Figs. l2 and 3.

In order to `'.'iccomplish .the above-mentioned shift in image transmission, the .mechanism 36 comprises a shutter 38, see Fig. l1, which is pivotally mounted upon Aa stationary pin 40 and normallyurged-tofa position infront of the .lens

stops 39 and 4I, as by means of A rod 43, having an enlarged end an opening 46 in the end of the shutter and when moved downwardly by the actuating device 26, serves to positively move the shutter to the dotted line position shown in Fig. '7 in order to allowfthe image from lens I6 to be transmitted'to ythe Amirror 20. Under these conditions, transmission of the image from mirror 28 to mirror 32 and thence to the tube I4 will be effected as illustrated in Fig. 2. In the event it is desired to select the wide angle lens I8, it is only necesary to cause the rod 43 to be movedupwardly whereupon the upper end thereof slips Yfreely through the opening 46 in the end ofthe shutter 38, and allows the shutter to block the transmission of the image from the lens I6 through movement thereof in response to the .action of therspring 42.

One of the features of the present invention resides in the elimination ,of all visual effects resulting from swimming images during the shift from one lens to the other. A novel arrangement is hence employed which insures that the light from the lens I6 willfbe intercepted by thefshutter 38 during the change in position of the vmirror. To this end, .the vrod 43 is provided with a lug cr abutment 41 which is adapted to engage and move the free .end .of a lever 48, pivotally mounted intermediate its-ends upon a stationary part 50, whenever the .rod 43 is moved upwardly. The opposite end of lever 48 is pivotally connected to the mirror .32 through a link 52, and adjacent the pivotal mounting 50, the lever 48 is influenced by a spring 5.4 which normally .urges the parts -including the mirror 32 to the position shown in Fig. A2. It .will be understood from this construction that during vupward movement of the rod 43, the lug 41 will engage the end of lever 48 andpositively move the mirror 32 to the position shown -in Fig. 3 only after sufficient movement of the rod 43 has taken place as Yto allow the shutter r38 to obstruct the light transmitted through the .lens I6. This i-s due to the novel construction employed, including the slip connection between rod 43 and shutter 38 .as well as the spacing of the lug 41 below the vfree end ,of lever 48, which allows complete obstruction of the lens I6 before movement of the mirror 32 and clearing .of the optical `path from lens I8, as shown in Fig. 3.

It will be understoodv that if it is desired to select the lens I6, the novel construction provided bythe present invention insures that the mirror .32 will be moved to the positionshown .in Fig. 2', under the influence of spring `54, to obstruct the .image transmission from lens I8, before the end 44 of the rod 43 contacts and moves the shutter 38 to clear the path from lens I6. Thus swimming of images during the transition from one lens to the other is completely avoided by the novel shutter and .pivoted mirror construction of thi-s form of the invention.

A further form of the invention is shown in Fig.4 which differs from the modification of Figs. 2 and 3 in that the mirrors 20 and 32 are constituted by relatively movable sections 56, 58 and 68, 62, the arrangement being such that when the sections are aligned, as shown in full lines in Fig. 4, the image from lens I6 will be transmitted to the screen or mosaic 64 by vreflection from mirrors and 32. On the other hand, when the sections of the mirrors are separated, as indicated in 75 from the wide angle lens I8 will be undisturbed,

I6, to engage a spring 42.

while that from shutter 51.

lens I 6 will be intercepted by a is pivotally connected to a reciprocating bar or lever 66 which is adapted to actuate a pair of arms 68 and 10, the latter being respectively connected with the mirror1 sections 58 and 62 and associated mirror sections 56 and 6U through suitable sector gear Normally, a spring 16 seeks to maintain the parts in the full line posithereafter the lug 41 engages and moves the lever 64 to open the mirror sections 56, 58 and 60, 62, thereby permitting the image from the wide angle lens I8 to be transmitted to the mosaic 64 of the tube I4. Upon opening of the mirror sections 56, '58, the image from lens I6 may be observed upon ground glass screen 61.

The form of the invention illustrated in Fig. 5 is substantially the same as that shown in Fig. 4, except that a modified form of actuating device is employed for moving the shutter 51 and the mirror sections 56, 58 and 60, 62. As shown, the actuating device comprises a bar 82, adapted to be moved upwardly or downwardly by the actuating device 26 for the purpose of rotating gears .84 and 86 through toothed sections 88, 96 formed on the bar. The gears 84 and 86 are respectively adapted to operate the sector gear transmissions move the mirror sections 56, 58 and 6U, position. When the mirror sections are closed they are adapted to contact suitable stops 92 and 94 and when in this position, the lens I6 is eiective. With the mirrors opened, as illustrated, lens I8 projects the image directly upon the mosaic of the tube I'4.

In order to insure that the sections of the mirrors 26 and 32 are closed before the shutter 51 is opened, a lug or abutment 95 is secured to the bar 82 to contact and actuate the arm 96 secured to the shutter 51 after closure of the mirror sections. Preferably, when the lug 95 contacts the arm 96, the toothed sections I6 and 90 on the bar 82 will clear the gears 84 and 86 and hence any additional movement of the bar 82 will serve to open the shutter 51 against the tension of springs 65 without operating the sections of the mirrors 20 and 32 which remain in c losed or aligned position. If desired, a staemployed for recording any desired scene. It will noted, that while several dilTerent ming or moving images upon photo-sensitive surface during the change from onelens to another, In addition to the foregoing, the use of the inertia operated shutter device disclosed herein, completely avoids the undesirable visualy effectsdueto a rapid panning movement of the camera.

While the invention has been particularly described in connection with a television camera, it will be understood that the same is equally adaptable to any cam'era provided with a photosensitive surface on which scenes are to be recorded and. wherein a plurality of lenses having different focal lengths are utilized. Moreover, while several embodiments of the invention have been illustrated' and described herein, it will be understood that the same is not limited to these forms but is capable of a variety of expressions, aswill readily appear to those skilled in the art, without departing' from the spirit of the invention. Reference will therefore be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. Ina camera having a photo-sensitive surf-ace andl a pair of lenses, the optical axis of one lens being aligned to transmit an image directly to saidsurface, and the optical axis of the other lens being offset from said surface, means including. a pair of spaced-apart angularly positioned mirrors for transmitting an image indirectly from saidv other lens to the photo-sensitive surface, o ne of said mirrors being positioned to intercept the image transmission from said one lens to the surface when said mirrors transmit the image fromv said other lens, and means for interrupting the image transmission from said other lens to the surface, and establishing the image transmission from said one lens to the surface, including a device for sequentially positively intercepting image transmission from said other lens to the surf-ace and for then moving said. one mirror out of its image intercepting position.

2. In a camera having a photo-sensitive surface and a pair of lenses, one of said lenses having its optical axisaligned to transmit an image directly tov said surface and the other lens having its optical axis offset with respect to said surface, means including a pair of spaced-apart angularly positioned light reflecting members for transmitting. an image indirectly from said other lens to the surface, one of said members being positioned in the optical path from said one lens to the surface and intercepting the image transmission from said one lens to the surface when the members transmit the image indirectly from said other lens, and means for interrupting the indirectimage transmission from said other lens to the surface, and establishing the direct image transmission from' said one lens to the surface, including a movable shutter, and connections between the shutter and said one light reflecting member for rstmoving the shutter to interrupt image transmission from said other lens to the surface. and for thereafter moving said one light reecting member out of the optical path between said one lens and surface.

3. In a television camera having a photo-sensitive surface and a pair of lenses, the optical axis of one lens being aligned to transmit an image directly to said sensitive surface, and the optical axis of the other lens being offset from said sensitive surface, means to transmit an image indirectly from sai Y optical offset lens to said photo-sensitive surf-ace including a pivotally movable lighty reflecting, member, said lightL refleeting member being; alternatelyV positioned in the optical path from said optically aligned lens to said surface and intercepting image transmission from said alignedf lens to said surface when said light reflecting. member transmits the image from said offset lens to said surface, and means for interrupting image transmission from said offset lens to the surface and establishing image transmission from said aligned lens to said surface including a movable shutter and mechanical linkage between said shutter and said light reflecting member, said linkage cooperative sequentially fory first moving said shutter to4 interrupt image transmission from said offset lens to the surface andQ for thereafter moving said light reflecting member out of the optical'path between said aligned lens; and surface.

4. In a camera havingI a substantially flat photo-sensitivesurface and au pair of optical systems for separately projecting an image on said surface, oney of said systems includingv a lens having its optical axis aligned to transmit an image directly to said surface, and the other system including a lenshaving its optical axis offset from said surface, means included in said other system for transmitting: anv image indirectly from said optically offset lens to said surface including a pair of angularly positioned spaced apart light reflectingv members, one member being positioned in the optical path from the optically aligned lens to thee surface and including a pair of pivoted sections arranged in closed. and aligned position to simultaneously transmit the image indirectly .from said optically-offset lens to said surface and to interceptY direct image transmission from the optically'y aligned lens tosaid surface, and means for interrupting indirect image transmission from saidf offset lens tothesurface and establishing direct image transmission from said aligned-lens to said surface comprising a movable shutter, and mechanical linkage between the shutter and the pivoted sections of said member for sequentiallyv moving said= shutter to interrupt indirect image` transmission from' the offset lens to the surface and for thereafter moving said pivoted sections toY an openV position out of the optical path betweenther aligned lens and said surface.

THORNTON W. CHEW.

REFERENCES CITED The following. references are-r of record in thc file of this patent:

UNITED STATES' PATENTS Number Name Date 1,275,249 Hlavaty Apr. 13, 1918 1,310,776 Akeley July 22, 1919 1,326,379v Thompson. Dec. 30, 1919 1,505,268 Larson; Aug. 19, 1924 1,525,741 Hutchings Feb. 10, 1925 1,744,788 Mery Jan'` 28, 1980 1,795,626 Watkins Mar. 10, 1931 1,809,338 Hayden June 9, 1931 1,854,132 Ginsberg Apr. 12, 1932 1,873,571 Fried Aug. 23, 1932 1,967,468 Douglass July 24, 1934 2,120,654 Spence etal June 14, 1938 2,153,198 Mihalyry Apr. 4, 1939 2,377,954 Melli'en June 12, 1945 FOREIGN PATENTS Number Country- Date 22,985 GreatBritain; 1911 

